Polypropylene-based resins have high stiffness, heat resistance and processability. However, in applications which require high impact resistance, low temperature performance, dimensional stability and paintability, such as automotive parts and domestic appliances, polypropylene-based resins fall short. Therefore, attempts have been made to improve the above short comings of polypropylene-based resins, for example, adding copolymers of ethylene with alpha-olefins.
U.S. Pat. No. 5,001,182 describes a resin composition comprising a crystalline propylene-ethylene block copolymer, which contains a propylene polymer component, a propylene-ethylene copolymer component and an ethylene copolymer component; (b) a non-crystalline ethylene-C.sub.3-6 alpha-olefin random copolymer component; and (c) a talc or calcium carbonate component.
In EP 0 519 725 disclosed is a thermoplastic polymer composition comprising a thermoplastic polymer component comprising an ethylene-propylene rubber, and ethylene copolymer and a propylene polymer, which is blended with talc. A similar composition is disclosed in EP 0 496 625.